title: Diverse associations in the ternary systems of β-cyclodextrin, simple carbohydrates and phenyl derivatives of inorganic oxoacids.
abstract: Complex formation reactions of phenylboronic, phenylphosphonic, phenylarsonic and 4-aminophenyl arsonic acids with β-cyclodextrin (cycloheptaamylose, β-CD) and some simple carbohydrates (mannitol, sorbitol, glucose) have been studied using spectrophotometric, potentiometric methods and solubility measurements, supplemented with HPLC and IR analyses of the solid samples. Equilibrium constants have been determined at ionic strength of 0.2M (NaCl) and 25°C. β-CD forms the most stable complexes with the neutral, undissociated forms of the acids, the stability constants are as follows: phenylboronic acid: 320 ± 36, phenylphosphonic acid: 108 ± 25, phenylarsonic acid: 97 ± 4 and 4-aminophenyl arsonic acid: 107 ± 10. The stability constants for the β-CD-complexes of the ionic forms are much lower. Ternary complexes of low stability could be detected in the case of phenylphosphonic acid and sorbitol with the undissociated form and with glucose and the dianion. In more concentrated solutions phenylboronic acid forms insoluble complexes with mannitol, sorbitol and β-CD. The solid phases obtained in the ternary systems are predominantly mixtures of ester type 3:1 complexes with the carbohydrate and 1:1 inclusion complex with the β-CD. No significant interaction has been found with glucose. The phenomena can be explained by the differences in the structures of the components and by the changes in the H-bonding network of β-CD on the complex formation.
authors.affiliation: Institute of Chemistry, Loránd Eötvös University, Pázmány sétány 1/A, H-1117 Budapest (H-1518 Budapest, PO Box 32), Hungary.
authors.forename: Zita
authors.initials: Z
authors.lastname: Sebestyén
authors.forename: Katalin
authors.initials: K
authors.lastname: Máthé
authors.forename: Agnes
authors.initials: A
authors.lastname: Buvári-Barcza
authors.forename: Elemér
authors.initials: E
authors.lastname: Vass
authors.forename: Ferenc
authors.initials: F
authors.lastname: Ruff
authors.forename: Julianna
authors.initials: J
authors.lastname: Szemán
authors.forename: Lajos
authors.initials: L
authors.lastname: Barcza
mesh_terms: D001897:Boronic Acids / Q000737:chemistry; D005947:Glucose / Q000737:chemistry; D011199:Potentiometry; D013012:Sorbitol / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D001897:Boronic Acids; D047392:beta-Cyclodextrins; D013012:Sorbitol; D005947:Glucose; C031215:betadex; C010686:benzeneboronic acid